BY K. GREIG SMITH. 829 



this case. The culture was evaporated to smaller volume and 

 heated after hydrochloric acid had been added to make a 1 % 

 solution. The acid filtrate was made alkaline, whereupon the 

 difficultly hydrolysable carbohydrate was precipitated, while the 

 easily hydrolysable constituent remained in solution. The latter 

 was purified by repeated precipitation with alcohol, the former 

 by solution in acid and precipitation with alkali until all reducing 

 sugars had been eliminated. As in the former case, the soluble 

 substance was completely hydrolysed to galactose and a glucose, 

 while the insoluble carbohydrate was not attacked. 



What the nature of the glucose was, I did not endeavour to 

 determine. The object of the research was to prove the presence 

 or absence of arabin or metarabin among the products of 

 Dematium pulhdans. The absence of arabinose among the 

 sugars of the water- and alkali-soluble portion showed that 

 neither of these gums is a product of the organism. 



Remembering that Kossel"^ had shown that the nucleic acid of 

 yeast when boiled with dilute hydrochloric acid gives a mixture 

 of a glucose and a pentose, it occurred to me that the glucose and 

 galactose that I had obtained had in all probability been derived 

 from the nucleic acid of the fungoid nucleoproteid. That they 

 had been so derived was shown by the absence of carbohydrates, 

 soluble in dilute alkali, in the viscous filtrate from a culture of 

 the mould in a saccharose-peptone fluid which contained chalk. 

 It can therefore be accepted that the glucose and galactose had 

 been derived from the proteids of the Dematium and should not 

 be considered as having been derived from the slime products of 

 the organism. 



Upon finding that the constituent insoluble in dilute alkali 

 could not be hydrolysed, the dilute acid solution Was evaj^orated 

 down upon the water-bath until it charred. At this stage it 

 showed traces of reducing sugars when tested with Fehling's 

 solution. The dark-coloured liquid was diluted with water to 

 the original volume and boiled for some hours under an aerial 

 condenser. After removal of the sulphuric acid and concentra- 



* Lafar, Technical Mycology II., i., 162. 

 53 



